Revert "Change worker exit to use exit instead of exit!."

This reverts commit f3bbf99.

Every job is failing with a DirtyExit when the bang is removed.

Author: defunkt

lib/resque/worker.rb

@@ -128,7 +128,7 @@ def work(interval = 5.0, &block)
           else
             procline "Processing #{job.queue} since #{Time.now.to_i}"
             perform(job, &block)
-            exit unless @cant_fork
+            exit! unless @cant_fork
           end
 
           done_working
@@ -302,7 +302,7 @@ def kill_child
     def paused?
       @paused
     end
-
+    
     # Stop processing jobs after the current one has completed (if we're
     # currently running one).
     def pause_processing